Earlier on Tuesday, the prime minister was filmed at a Buckingham Palace event to mark the Queen’s 90th birthday also making unguarded comments.

Talking about this week’s anti-corruption summit in London, he said: “We’ve got some leaders of some fantastically corrupt countries coming to Britain. Nigeria and Afghanistan, possibly the two most corrupt countries in the world.”

The Archbishop of Canterbury Justin Welby intervened to say: “But this particular president is not corrupt. He’s trying very hard.” before Speaker John Bercow said: “They are coming at their own expense, one assumes?”